21939646488 has 32 divisors (see below), whose sum is σ = 54863692800. Its totient is φ = 7311271968.

The previous prime is 21939646481. The next prime is 21939646493. The reversal of 21939646488 is 88464693912.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21939646481) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27808 + ... + 211311.

It is an arithmetic number, because the mean of its divisors is an integer number (1714490400).

Almost surely, 2^21939646488 is an apocalyptic number.

It is an amenable number.

21939646488 is an abundant number, since it is smaller than the sum of its proper divisors (32924046312).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21939646488 is a wasteful number, since it uses less digits than its factorization.

21939646488 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 242951 (or 242947 counting only the distinct ones).

The product of its digits is 17915904, while the sum is 60.

The spelling of 21939646488 in words is "twenty-one billion, nine hundred thirty-nine million, six hundred forty-six thousand, four hundred eighty-eight".